DNA Extraction from Wheat Germ Lab

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DNA Extraction from Wheat Germ Lab

• Data Questions

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Background Information

• Wheat germ comes from wheat seeds. The germ is
  the embryo, which is part of the seed that can
  grow into a new wheat plant. When wheat seeds are
  milled into white flour, the wheat germ and wheat
  bran are removed, leaving only starch. Wheat germ
  contains many nutrients while wheat bran consists
  of fiber. Whole wheat flour contains all parts of
  the wheat seed and is therefore more nutritious
  than white flour while also providing important
  fiber for digestion.

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Background Information Water Temperature

• The heat softens the phospholipids (fats) in the
  membranes that surround the cell and the nucleus.
  It also inactivates (denatures) the
  deoxyribonuclease enzymes (DNase)which, if
  present, would cut the DNA into such small
  fragments that it would not be visible. Denatured
  enzymes and DNA unravel, lose their shape, and
  thus become inactive. Enzymes denature at 60
  degrees celcius, and DNA denatures at 80 degrees
  celcius.

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Background Information Detergent

• Detergent contains sodium laurel sulfate, which
  cleans dishes by removing fats and proteins. It
  acts the same way in the DNA extraction protocol,
  pulling apart the fats and proteins that make up
  the membranes surrounding the cell and nucleus.
  Once these membranes are broken apart, the DNA is
  released from the cell. A cells membranes have
  two layers of lipid (fat) molecules with proteins
  going through them. When detergent comes close to
  the cell, it captures the lipids and proteins and
  releases the DNA.

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Background Information Alcohol

• The DNA released from the cell nucleus is
  dissolved in the water/detergent/wheat germ
  solution and cannot be seen. DNA precipitates out
  of the solution in alcohol, where it can be seen.
  Besides allowing us to see the DNA, the alcohol
  separates the DNA from the other cell components,
  which are left behind in the water solution.

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• Data
• 1. How many grams of wheat germ were used in this
  experiment?
• 2. How many mL of warm water did you use? What
  was the temperature of water?
• 3. What is the purpose of using warm water in
  this experiment?
• 4. How many teaspoons of detergent did you use?
• 5. What is the purpose of using alcohol in this
  experiment?

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• 6. Where in the cell DNA is located?
• 7. What is the purpose of stirring the mixture of
  wheat germ, warm water and liquid soap? What will
  happen to DNA if you speed up the stirring
  process?
• 8. Why cant you use cooked food for your sample
  of DNA?
• 9. What part of the cell would the detergent work
  on?
• 10. Why is keeping a record of what you did
  important?

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• 11. What are the three chemicals that constitute
  the cell membrane?
• 12. What chemicals make up the nuclear membrane?
• 13. What is the effect of soap on the cell
  membrane on the nuclear membrane?
• 14. What is the effect of alcohol on the cell
  membrane on the nuclear membrane?
• 15. You do not have to do.
• 16. Describe the physical appearance of your
  extracted DNA.
• 17. What are some possible errors in this
  experiment?
• 18. What did you learn from this experiment?